(38) HTML (Form Elements)
HTML5 Form Elements
HTML5 added the following form elements: <datalist> <output> Note: Browsers do not display unknown elements. New elements that are not supported in older browsers will not "destroy" your web page.
HTML Form Elements
Tag Description <form> Defines an HTML form for user input <input> Defines an input control <textarea> Defines a multiline input control (text area) <label> Defines a label for an <input> element <fieldset> Groups related elements in a form <legend> Defines a caption for a <fieldset> element <select> Defines a drop-down list <optgroup> Defines a group of related options in a drop-down list <option> Defines an option in a drop-down list <button> Defines a clickable button <datalist> Specifies a list of pre-defined options for input controls <output> Defines the result of a calculation
The <button> Element
The <button> element defines a clickable button: Example <button type="button" onclick="alert('Hello World!')">Click Me!</button> Note: Always specify the type attribute for the button element. Different browsers may use different default types for the button element.
HTML5 <datalist> Element
The <datalist> element specifies a list of pre-defined options for an <input> element. Users will see a drop-down list of the pre-defined options as they input data. The list attribute of the <input> element, must refer to the id attribute of the <datalist> element. OperaSafariChromeFirefoxInternet Explorer Example <form action="/action_page.php"> <input list="browsers"> <datalist id="browsers"> <option value="Internet Explorer"> <option value="Firefox"> <option value="Chrome"> <option value="Opera"> <option value="Safari"> </datalist> </form>
The <fieldset> and <legend> Elements
The <fieldset> element is used to group related data in a form. The <legend> element defines a caption for the <fieldset> element. <!DOCTYPE html> <html> <body> <h2>Grouping Form Data with Fieldset</h2> <p>The fieldset element is used to group related data in a form, and the legend element defines a caption for the fieldset element.</p> <form action="/action_page.php"> <fieldset> <legend>Personalia:</legend> <label for="fname">First name:</label><br> <input type="text" id="fname" name="fname" value="John"><br> <label for="lname">Last name:</label><br> <input type="text" id="lname" name="lname" value="Doe"><br><br> <input type="submit" value="Submit"> </fieldset> </form> </body> </html>
The <label> Element
The <label> element defines a label for several form elements. The <label> element is useful for screen-reader users, because the screen-reader will read out loud the label when the user focus on the input element. The <label> element also help users who have difficulty clicking on very small regions (such as radio buttons or checkboxes) - because when the user clicks the text within the <label> element, it toggles the radio button/checkbox. The for attribute of the <label> tag should be equal to the id attribute of the <input> element to bind them together.
HTML5 <output> Element
The <output> element represents the result of a calculation (like one performed by a script). OperaSafariChromeFirefoxInternet Explorer Example Perform a calculation and show the result in an <output> element: <form action="/action_page.php" oninput="x.value=parseInt(a.value)+parseInt(b.value)"> 0 <input type="range" id="a" name="a" value="50"> 100 + <input type="number" id="b" name="b" value="50"> = <output name="x" for="a b"></output> <br><br> <input type="submit"> </form>
The <select> Element
The <select> element defines a drop-down list: Example <select name="cars"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="fiat">Fiat</option> <option value="audi">Audi</option> </select> The <option> elements defines an option that can be selected. By default, the first item in the drop-down list is selected. To define a pre-selected option, add the selected attribute to the option: Example <option value="fiat" selected>Fiat</option>
The <textarea> Element
The <textarea> element defines a multi-line input field (a text area): Example <textarea name="message" rows="10" cols="30"> The cat was playing in the garden. </textarea> The rows attribute specifies the visible number of lines in a text area. The cols attribute specifies the visible width of a text area. This is how the HTML code above will be displayed in a browser: You can also define the size of the text area by using CSS: Example <textarea name="message" style="width:200px; height:600px;"> The cat was playing in the garden. </textarea>
The <input> Element
The most important form element is the <input> element. The <input> element can be displayed in several ways, depending on the type attribute. Example <input name="firstname" type="text"> If the type attribute is omitted, the input field gets the default type: "text".
Allow Multiple Selections:
Use the multiple attribute to allow the user to select more than one value: Example <select name="cars" size="4" multiple> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="fiat">Fiat</option> <option value="audi">Audi</option> </select>
Visible Values:
Use the size attribute to specify the number of visible values: Example <select name="cars" size="3"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="fiat">Fiat</option> <option value="audi">Audi</option> </select>
